In the case in which power for charging a secondary battery is supplied from a power supply device to a power receiving device that operates on power charged in the secondary battery, “wireless power supply methods” that do not use a cable to supply power are becoming more widespread. Wireless power supply methods include electromagnetic induction methods, which have been commercialized in motorized toothbrushes, electric shavers, and the like, and magnetic resonance methods, which have not yet been commercialized fully, but are being commercialized. With magnetic induction methods, the power supply device and the power receiving device are brought into close proximity to supply power. On the other hand, with magnetic resonance methods, power supply (three-dimensional (3D) power supply) is possible in a state in which the power supply device and the power receiving device are from several dozen centimeters to several meters apart, and in addition, a single power supply device can supply power to a plurality of power receiving devices.
In relation to the above, technology that sets priority levels for a plurality of to-be-charged devices placed in a charging zone has been disclosed. Also, with this technology, there is disclosed technology that, when charging the plurality of to-be-charged devices in a non-contacting manner, decides a current distribution to provide for charging each to-be-charged device based on the priority level of each to-be-charged device.